| 1 | /* |
| 2 | * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com> |
| 3 | * Copyright (C) 2013 David Goulet <dgoulet@efficios.com> |
| 4 | * |
| 5 | * SPDX-License-Identifier: GPL-2.0-only |
| 6 | * |
| 7 | */ |
| 8 | |
| 9 | #define _LGPL_SOURCE |
| 10 | #include "consumer-metadata-cache.hpp" |
| 11 | |
| 12 | #include <common/common.hpp> |
| 13 | #include <common/consumer/consumer.hpp> |
| 14 | #include <common/sessiond-comm/sessiond-comm.hpp> |
| 15 | #include <common/ust-consumer/ust-consumer.hpp> |
| 16 | #include <common/utils.hpp> |
| 17 | |
| 18 | #include <inttypes.h> |
| 19 | #include <pthread.h> |
| 20 | #include <stdlib.h> |
| 21 | #include <string.h> |
| 22 | #include <sys/types.h> |
| 23 | #include <unistd.h> |
| 24 | |
| 25 | enum metadata_cache_update_version_status { |
| 26 | METADATA_CACHE_UPDATE_STATUS_VERSION_UPDATED, |
| 27 | METADATA_CACHE_UPDATE_STATUS_VERSION_NOT_UPDATED, |
| 28 | }; |
| 29 | |
| 30 | extern struct lttng_consumer_global_data the_consumer_data; |
| 31 | |
| 32 | /* |
| 33 | * Reset the metadata cache. |
| 34 | */ |
| 35 | static void metadata_cache_reset(struct consumer_metadata_cache *cache) |
| 36 | { |
| 37 | const int ret = lttng_dynamic_buffer_set_size(&cache->contents, 0); |
| 38 | |
| 39 | LTTNG_ASSERT(ret == 0); |
| 40 | } |
| 41 | |
| 42 | /* |
| 43 | * Check if the metadata cache version changed. |
| 44 | * If it did, reset the metadata cache. |
| 45 | * The metadata cache lock MUST be held. |
| 46 | */ |
| 47 | static enum metadata_cache_update_version_status |
| 48 | metadata_cache_update_version(struct consumer_metadata_cache *cache, uint64_t version) |
| 49 | { |
| 50 | enum metadata_cache_update_version_status status; |
| 51 | |
| 52 | if (cache->version == version) { |
| 53 | status = METADATA_CACHE_UPDATE_STATUS_VERSION_NOT_UPDATED; |
| 54 | goto end; |
| 55 | } |
| 56 | |
| 57 | DBG("Metadata cache version update to %" PRIu64, version); |
| 58 | cache->version = version; |
| 59 | status = METADATA_CACHE_UPDATE_STATUS_VERSION_UPDATED; |
| 60 | |
| 61 | end: |
| 62 | return status; |
| 63 | } |
| 64 | |
| 65 | /* |
| 66 | * Write metadata to the cache, extend the cache if necessary. We support |
| 67 | * overlapping updates, but they need to be contiguous. Send the |
| 68 | * contiguous metadata in cache to the ring buffer. The metadata cache |
| 69 | * lock MUST be acquired to write in the cache. |
| 70 | * |
| 71 | * See `enum consumer_metadata_cache_write_status` for the meaning of the |
| 72 | * various returned status codes. |
| 73 | */ |
| 74 | enum consumer_metadata_cache_write_status |
| 75 | consumer_metadata_cache_write(struct consumer_metadata_cache *cache, |
| 76 | unsigned int offset, |
| 77 | unsigned int len, |
| 78 | uint64_t version, |
| 79 | const char *data) |
| 80 | { |
| 81 | int ret = 0; |
| 82 | enum consumer_metadata_cache_write_status status; |
| 83 | bool cache_is_invalidated = false; |
| 84 | uint64_t original_size; |
| 85 | |
| 86 | LTTNG_ASSERT(cache); |
| 87 | ASSERT_LOCKED(cache->lock); |
| 88 | original_size = cache->contents.size; |
| 89 | |
| 90 | if (metadata_cache_update_version(cache, version) == |
| 91 | METADATA_CACHE_UPDATE_STATUS_VERSION_UPDATED) { |
| 92 | metadata_cache_reset(cache); |
| 93 | cache_is_invalidated = true; |
| 94 | } |
| 95 | |
| 96 | DBG("Writing %u bytes from offset %u in metadata cache", len, offset); |
| 97 | if (offset + len > cache->contents.size) { |
| 98 | ret = lttng_dynamic_buffer_set_size(&cache->contents, offset + len); |
| 99 | if (ret) { |
| 100 | ERR("Extending metadata cache"); |
| 101 | status = CONSUMER_METADATA_CACHE_WRITE_STATUS_ERROR; |
| 102 | goto end; |
| 103 | } |
| 104 | } |
| 105 | |
| 106 | memcpy(cache->contents.data + offset, data, len); |
| 107 | |
| 108 | if (cache_is_invalidated) { |
| 109 | status = CONSUMER_METADATA_CACHE_WRITE_STATUS_INVALIDATED; |
| 110 | } else if (cache->contents.size > original_size) { |
| 111 | status = CONSUMER_METADATA_CACHE_WRITE_STATUS_APPENDED_CONTENT; |
| 112 | } else { |
| 113 | status = CONSUMER_METADATA_CACHE_WRITE_STATUS_NO_CHANGE; |
| 114 | LTTNG_ASSERT(cache->contents.size == original_size); |
| 115 | } |
| 116 | |
| 117 | end: |
| 118 | return status; |
| 119 | } |
| 120 | |
| 121 | /* |
| 122 | * Create the metadata cache, original allocated size: max_sb_size |
| 123 | * |
| 124 | * Return 0 on success, a negative value on error. |
| 125 | */ |
| 126 | int consumer_metadata_cache_allocate(struct lttng_consumer_channel *channel) |
| 127 | { |
| 128 | int ret; |
| 129 | |
| 130 | LTTNG_ASSERT(channel); |
| 131 | |
| 132 | channel->metadata_cache = zmalloc<consumer_metadata_cache>(); |
| 133 | if (!channel->metadata_cache) { |
| 134 | PERROR("zmalloc metadata cache struct"); |
| 135 | ret = -1; |
| 136 | goto end; |
| 137 | } |
| 138 | ret = pthread_mutex_init(&channel->metadata_cache->lock, nullptr); |
| 139 | if (ret != 0) { |
| 140 | PERROR("mutex init"); |
| 141 | goto end_free_cache; |
| 142 | } |
| 143 | |
| 144 | lttng_dynamic_buffer_init(&channel->metadata_cache->contents); |
| 145 | ret = lttng_dynamic_buffer_set_capacity(&channel->metadata_cache->contents, |
| 146 | DEFAULT_METADATA_CACHE_SIZE); |
| 147 | if (ret) { |
| 148 | PERROR("Failed to pre-allocate metadata cache storage of %d bytes on creation", |
| 149 | DEFAULT_METADATA_CACHE_SIZE); |
| 150 | ret = -1; |
| 151 | goto end_free_mutex; |
| 152 | } |
| 153 | |
| 154 | DBG("Allocated metadata cache: current capacity = %zu", |
| 155 | lttng_dynamic_buffer_get_capacity_left(&channel->metadata_cache->contents)); |
| 156 | |
| 157 | ret = 0; |
| 158 | goto end; |
| 159 | |
| 160 | end_free_mutex: |
| 161 | pthread_mutex_destroy(&channel->metadata_cache->lock); |
| 162 | end_free_cache: |
| 163 | free(channel->metadata_cache); |
| 164 | end: |
| 165 | return ret; |
| 166 | } |
| 167 | |
| 168 | /* |
| 169 | * Destroy and free the metadata cache |
| 170 | */ |
| 171 | void consumer_metadata_cache_destroy(struct lttng_consumer_channel *channel) |
| 172 | { |
| 173 | if (!channel || !channel->metadata_cache) { |
| 174 | return; |
| 175 | } |
| 176 | |
| 177 | DBG("Destroying metadata cache"); |
| 178 | |
| 179 | pthread_mutex_destroy(&channel->metadata_cache->lock); |
| 180 | lttng_dynamic_buffer_reset(&channel->metadata_cache->contents); |
| 181 | free(channel->metadata_cache); |
| 182 | } |
| 183 | |
| 184 | /* |
| 185 | * Check if the cache is flushed up to the offset passed in parameter. |
| 186 | * |
| 187 | * Return 0 if everything has been flushed, 1 if there is data not flushed. |
| 188 | */ |
| 189 | int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel, |
| 190 | uint64_t offset, |
| 191 | int timer) |
| 192 | { |
| 193 | int ret = 0; |
| 194 | struct lttng_consumer_stream *metadata_stream; |
| 195 | |
| 196 | LTTNG_ASSERT(channel); |
| 197 | LTTNG_ASSERT(channel->metadata_cache); |
| 198 | |
| 199 | /* |
| 200 | * If not called from a timer handler, we have to take the |
| 201 | * channel lock to be mutually exclusive with channel teardown. |
| 202 | * Timer handler does not need to take this lock because it is |
| 203 | * already synchronized by timer stop (and, more importantly, |
| 204 | * taking this lock in a timer handler would cause a deadlock). |
| 205 | */ |
| 206 | if (!timer) { |
| 207 | pthread_mutex_lock(&channel->lock); |
| 208 | } |
| 209 | pthread_mutex_lock(&channel->timer_lock); |
| 210 | metadata_stream = channel->metadata_stream; |
| 211 | if (!metadata_stream) { |
| 212 | /* |
| 213 | * Having no metadata stream means the channel is being destroyed so there |
| 214 | * is no cache to flush anymore. |
| 215 | */ |
| 216 | ret = 0; |
| 217 | goto end_unlock_channel; |
| 218 | } |
| 219 | |
| 220 | pthread_mutex_lock(&metadata_stream->lock); |
| 221 | pthread_mutex_lock(&channel->metadata_cache->lock); |
| 222 | |
| 223 | if (metadata_stream->ust_metadata_pushed >= offset) { |
| 224 | ret = 0; |
| 225 | } else if (channel->metadata_stream->endpoint_status != CONSUMER_ENDPOINT_ACTIVE) { |
| 226 | /* An inactive endpoint means we don't have to flush anymore. */ |
| 227 | ret = 0; |
| 228 | } else { |
| 229 | /* Still not completely flushed. */ |
| 230 | ret = 1; |
| 231 | } |
| 232 | |
| 233 | pthread_mutex_unlock(&channel->metadata_cache->lock); |
| 234 | pthread_mutex_unlock(&metadata_stream->lock); |
| 235 | end_unlock_channel: |
| 236 | pthread_mutex_unlock(&channel->timer_lock); |
| 237 | if (!timer) { |
| 238 | pthread_mutex_unlock(&channel->lock); |
| 239 | } |
| 240 | |
| 241 | return ret; |
| 242 | } |